kernel launch time way too long

Discussion created by laughingrice on Jun 10, 2011
Latest reply on Jun 11, 2011 by himanshu.gautam

I'm trying to convert some code to OpenCL under the e350 (brazos) architecture with windows 7 64bit (although the application is 32bit).

Timing the following three lines of code takes about 1.2ms

size_t globalSz[2] = {320, 240};


clEnqueueNDRangeKernel(queue, Test, 2, NULL, globalSz, NULL, 0, NULL, NULL);


I believe that kernel launch overhead should be more in the area of 30us, so I'm guessing that I'm doing something wrong. The kernel itself is just the empty kernel so that I'm only supposed to be seeing the kernel lauch overhead. The original C code runs for about 1ms, so 1.2 ms kernel lauch overhead is unacceptable. Any ideas what I may be doing wrong?